1. Technical Field
The invention relates generally to material handling systems, and particularly to palletizers for arranging articles on a pallet.
2. Related Prior Art
A palletizer is operable to arrange objects, such as beverage containers, into an organized pattern and place the objects onto a pallet. It is known to provide such palletizers with a container conveyor assembly, apparatus to organize the objects into a pattern, a pallet dispenser, a separator sheet dispenser and a main hoist for holding the pallet in a position to receive a layer of objects and to move the pallet and layers of objects so as to receive an additional layer of objects.
The invention provides a palletizer assembly having improved apparatus for handling pallets upon which objects are placed and for handling top frames which are placed on top of the uppermost tier of a stack of layers of objects. The pallet and top frame handling apparatus include improvements to the pallet hoist and the main hoist. The palletizer, including the pallet and top frame handler, incorporates a modular design permitting various features of the invention to be independently incorporated into the palletizer.
The invention simplifies operation of the palletizer assembly, thereby improving the service life of the palletizer and simplifying maintenance and manufacturability of the palletizer assembly.
More particularly, in one embodiment of the invention, the palletizer assembly includes a pallet dispenser and a pallet hoist. The pallet hoist lifts individual pallets into an elevated, staging position wherein the pallet is received by a top frame handler. The staging position is in close proximity to the top of the main hoist so that the pallet need travel only a minimal distance to an initialized position wherein the pallet is located in the main hoist and positioned to receive a first layer of objects.
The top frame handler moves a top frame from a stack of top frames to the staging position underneath a pallet in the staging position and subsequently transports the pallet and top frame into the main hoist. The movements of the pallets and top frames are coordinated by the pallet hoist and top frame handler so that movements of the pallet and top frame into the staging position occur during stacking of containers.
Upon completion of a stack of objects, the top frame handler moves into the main hoist, thereby positioning the pallet and top frame into position for stacking. Because the top frame, when in the staging position, is in close proximity to the top of the stack, the top frame is moved into position on top of a newly created stack of containers quickly.
The top frame handler then releases the top frame to drop onto the top tier of stack of layers of objects while the stack of containers is located within the main hoist.
The palletizer also includes a pallet lift located in the main frame shaft. At the time the top frame handler releases a top frame onto a newly created stack of layers of containers, the pallet lift in the main hoist removes the pallet from the top frame carrier and into the initialized position for receiving a first layer of objects. The pallet lift, which is mounted on the main hoist frame, also positions the pallet so as to be supported by the main hoist.
The palletizer thus provides apparatus for handling a pallet and a top frame in a manner which minimizes the distances the pallet and top frame must travel from respective storage positions into a stacked position with containers. When the pallet is in the staging position, the pallet is maintained in a position above a top frame immediately prior to introduction of the pallet and top frame into the main hoist. This placement of the pallet above the top frame prior to placement of the top frame on a stack of containers reduces the cycle time of the palletizer assembly.
Another advantage provided by the invention is the provision of a palletizer assembly that places a top frame on a stack of containers before the stack leaves the main hoist. Because the stack of containers is eventually moved laterally outside the confines of the main hoist, which can tend to cause tipping of the stack or disrupt the arrangement of the containers on the pallet, the placement of a top frame on the stack before such lateral movement occurs enhances the stability of the stack.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings.